Electric power is generally transmitted from generation plants to end users (industries, corporations, homeowners, etc.) via a transmission and distribution grid consisting of a network of power stations, transmission circuits, and substations interconnected by power-lines. Once at the end users, electricity can be used to power any number of devices. The transfer of alternating-current (AC) electric power to the end users most frequently takes the form of three-phase electric power, where three current waveforms are produced that are generally equal in magnitude and 120° out of phase to each other. If the load on a three-phase system is balanced equally among the phases, no current flows through a neutral point, which is an important design aspect of the electric grid, allowing for efficient use of transformer capacity, reduced materials (e.g., size of a neutral conductor), etc. However, there are many factors that may create imbalance between the phases, such as excess load usage, downed power-lines, etc.
The topology of the electric transmission grid typically considers the balancing of the three-phase system, such that each end user (and thus the end user's devices) is attached to the grid on a particular phase of the three phase distribution feeder (though certain customers may be connected to two or three phases of the feeder). Most often, however, the end users, and more specifically the end users' devices, are unaware of which phase they are operating upon.
In addition, distribution utility companies can benefit from having accurate distribution feeder (medium voltage/low voltage or “MV/LV” circuit) connectivity information in their software applications and data stores. This is especially useful for outage management and for convenient application to planning, construction, operations, and maintenance. It is, however, very challenging to try to construct or approximate the circuit model within a GIS environment due to the complexity of modeling the dynamic nature of an electrical network. While the utility may have an “as-built” database, it may differ from the actual grid for various reasons, including inaccurate or incomplete data capture on construction, and changes to circuits that are not reflected in updates to the database. In addition, circuit topology may change dynamically as feeder switches are operated in the course of either normal or emergency operations. Such changes result in an “as-operated” topology that is dynamic and is not reflected in the “as-built” database. The information on “as-operated” configurations may not be available to smart grid systems at a latency low enough for real time operation of smart grid applications.